Question

(a) Write two differences between lyophilic and lyophobic colloids.
(b) Give the names of two enzymes present in yeast. Also write equations of the enzyme catalysed reactions.
(c) Draw labeled diagram of Bredig's Arc method

Answer 1

(a) Differences between lyophilic and lyophobic colloids.

Lyophilic colloids	Lyophobic colloids
Affinity between disperse phase and dispersion medium is little.	Affinity between disperse phase and dispersion medium is strong.
These are irreversible colloids.	These are reversible colloids.

(b) The enzymes present in yeast are:
Sucrase (invertase), zymase, maltase (glucase), lactase, hexosephosphatase, reductase, carboxylase, melibiase, and endo-tryptase, proteolytic enzymes.
Zymase catalyzes the fermentation of glucose or fructose into ethanol and carbon dioxide.
$C_6{H}_{12}{O}_6\text{(glucose or fructose)}\stackrel{zymase}{\to }2C_2{H}_{5}OH\text{(ethanol)}+2C{O}_2\uparrow$
Invertase catalyzes the fermentation of sucrose into glucose and fructose
$C_{12}{H}_{22}{O}_{11}+H_{2}O\stackrel{\text{invertase}}{\to }{C}_6{H}_{12}{O}_6\text{(glucose)}+C_6{H}_{12}{O}_6\text{(Fructose)}$
(c) The labeled diagram of Bredig's Arc method is as shown. This method is used to prepare colloidal solution of noble metals such as Au and Ag.